SM
A n a l y s i s o f C o m m o n M e t h o d s o f S t e r e o M a t c h i n g
Xinliang Zhong
Outline
· Introduction to stereo vision
· Overview of a stereo vision system
· Algorithms for stereo matching
· Applications
What is stereo vision
Is a technique aimed at inferring depth from
two or more cameras
Wide research topic in computer vision
This seminar is concerned with
binocular stereo vision systems
dense stereo algorithms
stereo vision applications
Applications
Single camera
Both (real) points (P and Q) project into the
same image point (p ≡ q)
This occurs for each point along the same line
of sight
Useful for optical illusions…
Stereo camera
With two (or more) cameras we can infer depth, by means of triangulation, if we are able to find corresponding
(homologous) points in the two images.
How to solve the correspondence problem
Epipolar constraint
Epipolar constraint
Disparity and depth
Overview of a stereo vision system
Calibrationoffline
Rectification
Stereo Correspondence
Triangulation
Key module in stereo vision?
The algorithm is crucial in this technology
The Stereo matching problem
According to the taxonomy proposed in [1] most stereo algorithms
(subset of) these steps:
1) Matching cost computation
2) Cost aggregation
3) Disparity computation/optimization
4) Disparity refinement
Local algorithms perform:
1 => 2 =>3 (with a simple Winner Takes All (WTA) strategy)
Global Algorithms perform:
1 (=>2) =>3 (with global or semi-global reasoning)
[1] D. Scharstein and R. Szeliski, A taxonomy and evaluation of dense two-frame stereo correspondence
algorithms Int. Jour. Computer Vision, 47(1/2/3):742, 2002
References